Tagged Questions

A stream cipher is an encryption algorithm which encrypts arbitrary length plain text, using a (fixed length) key. Some stream ciphers generate a key stream from only the key, which is then XOR-combined with the plain text, others feed back plain text or cryptotext into the algorithm to create the ...

I am trying to solve the following sipher
Nosdhiibotidcylhrdeovedljuetre
I have no experience with ciphers but substitution didn't seem to work, and since its a long string without breaks process of ...

I have 38 16-byte messages and 1 15-byte message encrypted using ARC4.
https://www.dlitz.net/software/pycrypto/api/current/Crypto.Cipher.ARC4-module.html
The same keystream was used in all messages. ...

A stream cipher usually generates a stream of pseudo-random bits which get XORed with the plaintext to form the ciphertext. The stream is generated using a given IV / nonce and a secret key. CTR-mode ...

say that we have an unknown stream cipher which output bytes and which have more than 10 years of existence. What can be the most probable algorithms if we consider the most 'populars' stream cipher ...

What is the general idea of truncated differential attack on hash functions ? i'm using stream cipher and sponge hash construction and i want to know what is the general idea of differential attack ...

I can precompute the key stream for the CTR mode operation and the encryption at that point is similar to a stream cipher. So why are there stream ciphers still used and proposed after RC4? Recently ...

We know that in stream cipher algorithms plain text and generated key are Xored byte by byte. Generated key depends on how much plain text there is and on that basis key will generate and plain text ...

Stream ciphers are vulnerable to replay attack if the same key k is used.
If E() is a stream cipher and an attacker intercepts the message m that's being transmitted at time t, how can the attacker ...

I have to come up with a design for a cryptography system by combining a block cipher and a stream cipher. I can't seem to come up with anything on my own. Can someone point me in the right direction ...

I want to encrypt a large file using RC4. But what happens if the encrypted file gets corrupted (bytes modified or lost)? Can I still decrypt the rest of the file correctly?
If not, what is the best ...

I'm doing a lot of research since I'm doing an internship for a company where I need to upgrade their security level. Their own protocol needs a cryptographic upgrade and I'm leaning towards AES since ...

I'm particulary interested on knowing if the output of the AES-128-CTR ciphertext is always going to have the same size as the input plaintext, or it could be padded somehow. It seems so from my tests ...

I was being argued that stream cipher's key that is the length of the message must be sent to the destination for them to be able to decrypt the message.
My point is don't you only have to send the ...

The AEAD construction for chacha20-poly1305 described in the IETF proposal [1] encodes message lengths into the text that is to be hashed. The newer proposal [2] goes further and pads associated data ...

If a wise person was unsure about which commercial cryptography standards are truly secure from the fascist powers that be, it would seem the obvious option for companies and individuals is to now use ...

I am currently implementing Salsa20 from the specification as an exercise in learning and self-flagellation.
I have Sections 1-7 passing the test examples provided. I am now stuck on Section 8, The ...

To obfuscate data I made up this method on the spot without planning since the goal wasn't real encryption.
At first I though this cannot be real encryption but after revisiting the code and reading ...

I learnt that a Combined Linear Congruential Generator (cLCG) has better properties than a Linear Congruential Generator (LCG). For those who don't know what a cLCG is, here are three links that might ...

I am making an encryptor software for a stream cipher with my own PRNG as a project for an inter school science competition. How can I make one so that after it generates the pseudo random nos. it can ...

I am trying to make a pseudo-random number generator so that I can use it in a synchronous stream cipher for encrypting plain text. I want it to generate numbers which are as random as possible.
What ...

Recently, a new cipher called Spritz has been released by Ronald L. Rivest and Jacob Schuldt. It should be a "drop-in replacement" for RC4.
There are many differences to RC4, Spritz is "spongy" and ...

I am learning about LFSR sequence and I came across this question:
A 16-bit message consists of two ASCII characters. This message was encrypted
with a one-time pad, and the key for the one-time pad ...